Fire Gel for spinners can actually cause more harm than good.
It causes the skin to be slippery, and leads to a false sense of security. It still warms up and you can still be burned, which is why it is usually slathered over kevlar clothing (such as the types stunt men/race car drivers wear).
These are usually only available to licensed Pyrotechnics anyway.
Biofax and other dips are just that. They are theatrical or upholstery dips that are used for curtains and carpets.www.theaterhouse.com
sells them. Again, they tend to be overkill for those who do not spin often or are not professional.
They leave a white-ish film on fabric, and everytime the fabric is washed it must be redipped, so it is not cost effective for the backyard spinner.
In the HoP articles there is one about fabrics and their burn times, and relative safety. Check it out.
Stick to heavy-ish natural materials and do not put on lotions, sunscreens, bugsprays, etc. before spinning.
As for hair, I have been doing this for years. I have always had longish hair and I have never done anything but pull it back and make sure it is damp (not soaked, just damp). I don't even cover my head.
I appreciate your level of concern though.
Hope this helps!